Preparation of aligned poly(glycerol sebacate) fibrous membranes for anisotropic tissue engineering

The use of fibrous scaffolds for tissue repair or regeneration is advantageous for its microstructure similar to that of the native ECM. Aligned fibrous scaffold, in particular, can be used to manipulate cell alignment and hence the microstructure of the resultant tissue. In our previous study, nanofibers consisting of solely poly(glycerol sebacate) (PGS) have been successfully fabricated using core-shell coaxial electrospinning followed by curing and subsequent shell removal. When we tried to fabricate aligned PGS fibrous membranes by collecting the electrospun fibers on a rapidly rotating drum, however, loss of fibrous structure was observed upon curing. This might be due to the broken fibers that were collected under tension; the core PGS prepolymer that melts at high temperature could leak from the broken ends during curing. In this study, attempts were made to reduce the possibility of the fiber breakage. At each stage of preparation, fiber morphology was examined by SEM and fiber compositions were verified by Fourier transform infrared spectroscopy and differential scanning calorimetry. Mechanical properties of the aligned PGS fibrous membrane were evaluated by uniaxial tensile testing both in parallel and perpendicular to the principal fiber direction. SEM images showed that fibrous morphology was better preserved upon the adjustment of the shell composition and the rotational speed of the collector drum. The final PGS fibers remained to be aligned although the alignment was less strong than that of as-spun coreshell fibers. The aligned PGS fibrous membrane exhibited anisotropic mechanical properties with Young's modulus in parallel and perpendicular to the principal fiber direction being 0.98 +/- 0.04 MPa and 0.52 +/- 0.02 MPa, respectively. The aligned PGS fibrous membrane was capable of guiding the orientation of cultured cells and therefore has the potential to be used to fabricate structurally anisotropic tissue-engineered constructs.